The present invention relates to an outboard marine drive with an internal combustion engine, particularly to an outboard marine drive with an internal combustion engine having a generally vertically extending crankshaft and an oil pan located generally below a cylinder block.
Conventionally, in an outboard marine drive with an internal combustion engine having a vertical crankshaft, an oil pan of the internal combustion engine is usually mounted at a position under a cylinder block and offset towards a cylinder head so as not to interfere with a drive shaft which vertically extends along an axis of the crankshaft. In such an arrangement, when the outboard marine drive is attached to a stern plate of a watercraft, the oil pan is located at a rearward position away from the stern plate.
On the other hand, it is desirable that the amount of oil in the oil pan can be checked easily by just detaching an engine cover for covering an upper part of the engine, and in this point of view, it is preferred that a receptacle of an oil level gauge consisting of a stick-like member is provided at an easily accessible position, i.e., as closely to the stern plate as possible and at as high as possible.
However, in a V-shaped engine having a pair of cylinder heads projecting out in lateral directions, it is difficult to provide the receptacle of the oil level gauge at such an easily accessible position. Thus, in order to solve such a problem, Japanese Utility Model Application Laid-Open Publication No. 5-911 has proposed a configuration in which an oil level gauge guiding tube is provided at a position between a pair of cylinder banks forming a V-shape and extends in parallel with a crankshaft.
In the configuration proposed in the above publication, however, although the oil level gauge can be passed through and pulled out from the top of the engine, the guiding tube provided between the pair of cylinder banks needs to have substantially the same length as the overall engine dimension in a direction along the crankshaft, and the oil level gauge needs to have an extension part that corresponds to the length of the crankshaft and that does not serve for oil level inspection, whereby leading to a higher manufacturing cost. Also, the lengthy oil level gauge tends to cause a difficulty in its insertion and removal operations.
In view of such problems of the prior art, a primary object of the present invention is to provide an outboard marine drive with an internal combustion engine having a vertically extending crankshaft which can improve the work efficiency of the oil amount inspection without causing an increase in the manufacturing cost.
A second object of the present invention is to provide an outboard marine drive with an internal combustion engine having a vertically extending crankshaft which can avoid using an unnecessarily lengthy oil level gauge to thereby allow easy handling of the oil level gauge.
According to the present invention, such objects can be accomplished by providing an outboard marine drive, comprising: an internal combustion engine having a crankshaft which extends generally vertically; a drive shaft extending generally vertically and operably connected to the crankshaft so as to transmit an output from the internal combustion engine to a propeller connected to a lower end of the drive shaft; the internal combustion engine comprising a cylinder block, an oil pan located generally below the cylinder block so as not to interfere with the drive shaft, and a stick-like oil level gauge for inspecting an amount of oil in the oil pan, wherein one sidewall of the cylinder block is provided with an insertion hole for allowing the oil level gauge to be passed therethrough into the oil pan.
Thus, since the insertion hole of the oil level gauge is formed in the sidewall of the cylinder block, the length of the oil level gauge can be significantly decreased compared with the conventional oil level gauge which is inserted from the top of the engine, and therefore, the insertion and removal operations of the oil level gauge can be considerably facilitated. Further, the insertion hole formed in the sidewall of the cylinder block can allow a handle of the oil level gauge received in the insertion hole to be placed near the stern plate of the watercraft, and therefore, the user can easily access the oil level gauge to inspect the amount of oil. Thus, an oil level inspection work can be considerably facilitated.
Preferably, the oil pan comprises a main reservoir part located generally below the cylinder block and at the rear of the drive shaft, and the insertion hole of the oil level gauge is provided at such a position that an axis of the oil level gauge is inclined forwardly and upwardly in an outward direction from a central portion of the main reservoir part of the oil pan when the oil level gauge is fully inserted into the insertion hole. This can allow the handle of the oil level gauge to project from the insertion hole sideways and forwardly (or towards the stern plate) when the oil level gauge is received in the insertion hole, and therefore the user can easily pull out the handle of the oil level gauge to inspect the oil level.
Particularly, if the cylinder block comprises: a pair of cylinder banks arranged in a V-shape diverging in a rearward direction when seen in a plan view; and a skirt portion provided in a front portion of the cylinder block to constitute part of a crankcase for accommodating the crankshaft therein, it will be preferable that the insertion hole of the oil level gauge is formed at a part of an outer sidewall of either one of the pair of cylinder banks near the skirt portion. This can place the insertion hole at an easily accessible position while favorably defining the direction of axis of the oil level gauge received in the insertion hole. Further, because the part of an outer sidewall of one of the pair of cylinder banks near the skirt portion is recessed when seen in a plan view, projection of the handle of the oil level gauge from an outer profile of the engine can be eliminated or minimized.
When the cylinder block comprises an oil return passage for allowing the oil to return to the oil pan from a cam chamber defined in a cylinder head provided at a rear end of the cylinder block, it is preferable that the insertion hole of the oil level gauge consists of a cast hole for defining a part of the oil return passage. This can make it unnecessary to separately form the insertion hole, and thus simplify the manufacturing process.
More preferably, the insertion hole of the oil level gauge is covered by a cover provided with a receptacle which is adapted to guide insertion of the oil level gauge into the insertion hole. The cover may consist of a plate provided with a tube like member for constituting the receptacle. Such a cover with a receptacle can be made easily and at low cost, and favorably define the direction of axis of the oil level gauge passed therethrough.
Other and further objects, features and advantages of the invention will appear more fully from the following description.